This invention relates to floating apparatus used in well cementing operations and to methods for fabricating such apparatus. More particularly, this invention relates to floating apparatus having improved means for transferring a valve load to an outer case.
Typically, after a well for the production of oil and/or gas has been drilled, casing will be lowered into and cemented in the well. The weight of the casing, particularly with deep wells, creates a tremendous amount of stress and strain on equipment used to lower the casing into the well. In order to minimize that stress, floating equipment, such as, but not limited to, float collars and/or float shoes are used in the casing string.
The float equipment typically consists of a valve affixed to the outer case which allows fluid to flow down through the casing but prevents flow in the opposite direction. Because upward flow is obstructed, a portion of the weight of the casing will float or ride on the well fluid thus reducing the amount of weight carried by the equipment lowering the casing into the well. Once the casing is in position, cement is flowed down through the inner diameter of the casing, through the valve and into the annular space between the outer diameter of the casing and the well bore. After the cement job is complete, the valve keeps the cement below and behind the casing string.
Floating apparatus is usually fabricated by affixing a check valve in an outer case which is adapted to be threaded directly into a casing string. The valve is affixed by filling the annulus between the valve housing and the outer case with a high compressive strength cement to form a cement body portion. The cement body portion transfers the valve load to the outer case such that the valve remains securely affixed within the outer case as pressure is being applied thereto. However, the present invention provides improved means for affixing the valve in the floating apparatus; thus, providing effective and more economically produced floating apparatus.